The present disclosure relates to a lightweight and corrosion resistant abradable TiAl coating which can be applied to a gas turbine engine component.
Abradable coatings are applied to fan cases of gas turbine engines to improve engine efficiency by decreasing the gap between the tips of a fan blade and the fan case.
Certain abradable coatings have shown spallation. Corrosion internal to the coating can be significant and is suspected as playing a significant role in weakening the coating and making it susceptible to fatigue cracking and spallation. In addition to weakening by corrosion, the aluminum alloy forming the abradable coating has low ductility and may be a poor coefficient of thermal expansion match to the substrate forming the fan case, typically a titanium alloy. The low ductility of an 88/12 Al/Si alloy and mechanical and thermally induced strains may result in cracking of the coating and subsequent loss of coating chunks.